先化简,后求值: ( x x - 2 - 4 x 2 - 2 x ) ÷ x + 2 x 2 - x ,其中x满足 x 2 ﹣ x ﹣ 2 = 0 .
计算: 2021 0 + 3 - 1 ⋅ 9 - 2 sin 45 ° .
先化简,再求值: x 2 + 2 x + 1 x ÷ ( x - 1 x ) ,其中 x = 2 + 1 .
化简: ( a + 2 a 2 - 2 a - a - 1 a 2 - 4 a + 4 ) ÷ a - 4 a .
计算: 2 cos 45 ° + ( 1 3 ) - 1 - | - 3 | .
先化简,再求值: x x - 4 ⋅ ( x + 2 x 2 - 2 x - x - 1 x 2 - 4 x + 4 ) ,其中 x = 3 - 2 .